This invention relates generally to a system for detecting and predicting refrigerant charge levels within a heating ventilating and air conditioning system.
Typically a heating ventilating and air conditioning system (HVAC) includes a refrigerant circuit containing a desired amount of refrigerant. Loss of refrigerant can result in premature failure of HVAC system components. It is therefore desirable to detect and monitor the amount of refrigerant contained within the refrigerant circuit.
Loss of refrigerant typically occurs over time and at a very slow rate. It is desirable to detect the loss of refrigerant and predict a future level of refrigerant in order to optimally schedule maintenance and correction of any problems with the HVAC system.
Known systems for detecting refrigerant loss are capable of detecting a significant loss in refrigerant such that the HVAC no longer functions optimally. However such systems only measure current refrigerant levels, and do not predict future levels of refrigerant to prevent a system from reaching a level where the loss of refrigerant requires immediate attention.
Current known systems for detecting refrigerant level include the use of additional sensors distributed throughout the refrigerant system or the use of complex analytical techniques that diagnose data obtained from sensors. The use of additional sensors is costly, adds complexity and is therefore not desirable.
Other known systems gather large amounts of data and utilized statistical techniques for analysis. Statistical techniques require the gathering of statistically significant levels of data that are often difficult and cumbersome to manipulate. Further, statistical techniques that analyze large quantities of data are most applicable to systems where data is plentiful but the physical properties and operation of the system are not well known. However, in a HVAC system the exact opposite condition is present. That is the physical operation and relationship between parameters of the HVAC system are well known, while the large amounts of data are not normally readily available.
Accordingly it is desirable to develop a system for detecting refrigerant level and for predicting a future level of refrigerant for an HVAC system without the use of additional sensors or gathering prohibitive amounts of data.